Laser patterned adapters with waveguides and etched connectors for low cost alignment of optics to chips

ABSTRACT

By determining an alignment point for a photonic element in a substrate of a given material; applying, via a laser aligned with the photonic element according to the alignment point, an etching pattern to the photonic element to produce a patterned region and an un-patterned region in the photonic element, wherein applying the etching pattern alters a chemical bond in the given material for the patterned region of the photonic element that increases a reactivity of the given material to an etchant relative to a reactivity of the un-patterned region, and wherein the patterned region defines an engagement feature in the un-patterned region that is configured to engage with a mating feature on a Photonic Integrated Circuit (PIC); and removing the patterned region from the photonic element via the etchant, various systems and methods may make use of laser patterning in optical components to enable alignment of optics to chips.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. application Ser. No. 16/058,608entitled LASER PATTERNED ADAPTERS WITH WAVEGUIDES AND ETCHED CONNECTORSFOR LOW COST ALIGNMENT OF OPTICS TO CHIPS filed Aug. 8, 2018, which ishereby incorporated by reference in its entirety.

TECHNICAL FIELD

Embodiments presented in this disclosure generally relate to fabricatingfeatures in optoelectronic devices. More specifically, embodimentsdisclosed herein provide for the use of lasers to improve the etching ofphysical features in addition to optical features in photonic elements.

BACKGROUND

The discrete optical and electronic components of optoelectronic devicesare fabricated separately and later joined together to produce anassembled device. Various epoxies and engagement features may be used toensure that the optical and electronic components maintain proper jointsonce assembled, but due to the tolerances of these devices, the relativelocations of the features present in the optical and electroniccomponents is typically verified before finalizing assembly (e.g. curingthe epoxy).

BRIEF DESCRIPTION OF THE DRAWINGS

So that the manner in which the above-recited features of the presentdisclosure can be understood in detail, a more particular description ofthe disclosure, briefly summarized above, may be had by reference toembodiments, some of which are illustrated in the appended drawings. Itis to be noted, however, that the appended drawings illustrate onlytypical embodiments of this disclosure and are therefore not to beconsidered limiting of its scope, for the disclosure may admit to otherequally effective embodiments.

FIG. 1 illustrates an example optoelectronic device according to aspectsof the present disclosure.

FIGS. 2A-D illustrate various views of an example optoelectronic devicewith an optical adapter configured to optically couple for lineartransmission according to aspects of the present disclosure.

FIGS. 3A-D illustrate various views of an example optoelectronic devicewith an optical adapter configured to optically couple for evanescenttransmission according to aspects of the present disclosure.

FIGS. 4A-D illustrate various views of the photonic elements of anoptical adapter constructed as a multi-piece unit according to aspectsof the present disclosure.

FIGS. 5A-E illustrate various views of an example optoelectronic devicewith an optical adapter configured with open cable connectors accordingto aspects of the present disclosure.

FIGS. 6A-G illustrate various planar arrangements of waveguides withinan optical adapter according to aspects of the present disclosure.

FIG. 7 illustrates an example substrate layout according to aspects ofthe present disclosure.

FIGS. 8A-D illustrate detailed views of engaging engagement features andmating features of the optoelectronic assembly according to aspects ofthe present disclosure.

FIG. 9A illustrates mating the engagement feature with the matingfeature according to aspects of the present disclosure.

FIG. 9B illustrates engaging the engagement feature with the matingfeature according to aspects of the present disclosure.

FIG. 9C illustrates engagement the engagement feature with the matingfeature according to aspects of the present disclosure.

FIG. 10 is a flowchart illustrating high level operations of an examplemethod for the use of laser patterning in optical components accordingto aspects of the present disclosure.

To facilitate understanding, identical reference numerals have beenused, where possible, to designate identical elements that are common tothe figures. It is contemplated that elements disclosed in oneembodiment may be beneficially utilized on other embodiments withoutspecific recitation.

DESCRIPTION OF EXAMPLE EMBODIMENTS Overview

One embodiment presented in this disclosure provides a substratefabricated with laser patterned adapters with waveguides and etchedconnectors for low cost alignment of optics to chips, the substratecomprising: a light-transmissive material having a first side and asecond side opposite to the first side; a plurality of dies defined inthe light-transmissive material, each die of the plurality of diesincluding: a first pattern imparted on the light-transmissive materialby a laser, wherein the first pattern extends into thelight-transmissive material from the first side, the first patterndefining a patterned region of the light-transmissive material and anun-patterned region of the light-transmissive material, wherein achemical structure of the patterned region has an increased reactivityto an etchant relative to the un-patterned region, and wherein thepatterned region defines an engagement feature in the un-patternedregion that is configured to engage with a mating feature on a PhotonicIntegrated Circuit (PIC); and a second pattern imparted on thelight-transmissive material by the laser, wherein the second patternextends to neither the first side nor the second side, the secondpattern defining a permanent waveguide within the light-transmissivematerial resulting from a laser induced change in the material/crystalstructure, wherein the waveguide is aligned relative to the engagementfeature to optically couple with an integrated waveguide of the PIC.

Another embodiment presented in this disclosure provides a method forfabricating laser patterned adapters with waveguides and etchedconnectors for low cost alignment of optics to chips, the methodcomprising: determining an alignment point for a photonic element in asubstrate of a given material; applying, via a laser aligned with thephotonic element according to the alignment point, an etching pattern tothe photonic element to produce a patterned region and an un-patternedregion in the photonic element, wherein applying the etching patternalters a chemical bond in the given material for the patterned region ofthe photonic element that increases a reactivity of the given materialto an etchant relative to a reactivity of the un-patterned region, andwherein the patterned region defines an engagement feature in theun-patterned region that is configured to engage with a mating featureon a Photonic Integrated Circuit (PIC); and removing the patternedregion from the photonic element via the etchant.

A further embodiment presented in this disclosure provide a method forfabricating laser patterned adapters with waveguides and etchedconnectors for low cost alignment of optics to chips, the methodcomprising: imparting a first pattern on a light-transmissive materialby a laser, wherein the first pattern extends into thelight-transmissive material from a first side to a second side that isopposite to the first side, wherein the first pattern defines anun-patterned region of the light-transmissive material and a patternedregion of the light-transmissive material that has an increasedreactivity to an etchant relative to the un-patterned region, andwherein the patterned region defines an engagement feature in theun-patterned region that is configured to engage with a mating featureon a Photonic Integrated Circuit (PIC); and imparting a second patternon the light-transmissive material by the laser, wherein second patternextends to neither the first side nor the second side, the secondpattern defining a waveguide within the light-transmissive materialaligned relative to the engagement feature to optically couple with anintegrated waveguide of the PIC.

EXAMPLE EMBODIMENTS

The present disclosure provides systems and methods for the use of laserpatterning in optical components to affect the etch rate of the opticalcomponents and the optical components produced according to such systemsand methods. By applying laser light to an optical component, not onlycan the laser construct waveguides within the material matrix of theoptical component, but the laser may also change the material'ssusceptibility to chemical etching. The laser precisely imparts athree-dimensional pattern into the material to control what portions ofthe material have higher etching rates than the surrounding un-patternedmaterial, and may also impart three dimensional patterns that affect therefractive indices of the material to form waveguides. Once the etchantis applied, the patterned regions are removed at a faster rate than theun-patterned regions, and the optical component exhibits physicalfeatures that are co-aligned with the optical features (e.g.,waveguides). By co-aligning the optical and physical components andemploying the high degree of precision of laser patterning, the opticalcomponents avoid the need for active alignment and testing beforeintegration into an optoelectronic assembly, thus improving yields,improving speed of assembly, and reducing overlapping/stackingtolerances by providing more precisely toleranced components. Laserpatterning and chemical etching provides a higher degree of precision intolerancing the defined components than physical etching (e.g., ±hundreds of nanometers versus ± tens of micrometers (also referred to asmicrons)), and allow for components to be co-fabricated with fewer andless labor-intensive verification tests.

The laser used in laser patterning shines a high intensity light intothe material of the optical component (e.g., a SiO₂ based material) tobreak chemical bonds within the material to alter the light-transmissionproperties of the material and/or affect how readily the material reactswith an etchant. The etchant may include various acids (e.g., HCl, HNO₃,H₂SO₄) or other caustic compounds that bond with the patterned materialmore readily than the un-patterned material and that may be washed awayto remove material from the optical component. In some embodiments,laser patterning increases the reactivity of the material up to around5000 times the reactivity of the un-patterned material.

When patterning an optical component, the laser maintains a referencepoint (e.g., an edge of the optical component of a substrate containingseveral optical components) so that the beam precisely defines theportions of the material that are to become waveguides, and whatportions are to be removed during chemical etching. In some embodiments,establishing the waveguides using laser patterning is performedsimultaneously with defining the portions of material to remove. Inadditional embodiments, laser patterning is done prior to and thechemical etching is done after physical etching to allow a roughphysical removal of material followed by a more precise chemical removalof material, or to establish flow guides for the etchant prior tochemical etching.

FIG. 1 illustrates an example optoelectronic device 100 that includes anoptical adapter 110 and a Photonic Integrated Circuit (PIC) 120 in anexample arrangement. Each of the optical adapter 110 and the PIC 120 areexamples of optical elements that may be laser patterned according toembodiments of the present disclosure. The optical adapter 110 and thePIC 120 are each made of a glass material (such as SiO₂, which may bedoped with various dopants) or other light-transmissive material towhich a laser may be applied to selectively break or alter the chemicalbonds of that material to affect the reactivity of that material to achemical etchant; affecting the material or crystal structure of thesubstrate (i.e., the chemical structure). Various waveguides 115 in theOptical Adapter 110 and integrated waveguides 125 in the PIC 120 aredefined in the respective materials to establish distinct pathways overwhich beams of light may be propagated. In some embodiments, aphoto-receiver (e.g., a light-activated diode) connected to a waveguide115 receives a beam of light propagated from an external source, and inother embodiments a light source (e.g., a fiber optic cable or laser)connected to a waveguide 115 transmits a beam of light through thematerial.

The optical adapter 110 is a passive device that connects theoptoelectronic device 100 to various other devices or cabling. Forexample, the optical adapter 110 may be a Fiber Array Unit (FAU) toconnect the optoelectronic device 100 with various fiber optic cablingvia several individual light paths arranged in an array. In variousembodiments, the optical adapter 110 conforms to various standard shapesand sizes for optical connectors, including, but not limited to: MediaInterface Connector (MIC), Aviation Intermediate Maintenance (Avio),Diamond Micro Interface (DIM), IEC 61754 (and variants/offshootsthereof, such as Multiple-Fiber Push-On/Pull-Off), Enterprise SystemsConnection (ESCON), and the like. As such, the number of waveguides 115,the spacing and arrangement of waveguides 115, and various connectionpoints on the optical adapter 110 may vary based on the standard and howthe PIC 120 is arranged.

The PIC 120 is a photonic element that may operate to amplify, dim,extinguish, phase shift, switch, modulate, direct optical signals, andconvert optical signals to an electrical signal for use by an ElectricalIntegrated Circuit (EIC) integrated with or connected to the PIC 120.The EIC is an electrical circuit that operates with the PIC 120 to sendor receive and process optical signals. The EIC may include a processor,memory storage devices, communications interfaces to other electricalcircuits or equipment, and components to drive or receive opticalsignals via the PIC 120. The optical adapter 110 optically interfaceswith the PIC 120 to carry optical signals from the PIC 120 to externaldevices or to the PIC 120 from external devices. The optical adapter 110may physically interface with one or more of the EIC and the PIC 120 viavarious connectors and/or epoxies.

FIGS. 2A-D illustrate various views of an example optoelectronic device100 with an optical adapter 110 configured to optically couple with aPIC 120 for direct transmission. As will be appreciated, in a givenview, a given feature may be occluded or obscured by another feature,and a better understanding of how the features of an optoelectronicdevice interact may be gained by considering FIGS. 2A-D in aggregatethan individually.

FIG. 2A illustrates an isometric view of a translucent optical adapter110 that is affixed to and optically coupled with the PIC 120. As shown,engagement features 111 of the optical adapter 110 are engaged withmating features 121 of the PIC 120, and epoxy joints 130 are formedbetween the optical adapter 110 and the PIC 120. Epoxy joints 130 areformed via a deposited epoxy (e.g., in an epoxy well) being cured tobond one component to another. The optical adapter 110 shows cableconnectors 112 extending from a free surface 117, and a set ofwaveguides 115 that run from the free surface 117 of the optical adapter110 to an optical coupling interface 118 of the optical adapter 110 thatis held in contact with integrated waveguides 125 in the PIC 120. Amating interface 116 and an optical coupling interface 118 of theoptical adapter 110 may be collectively referred to as a connectingsurface, and although illustrated as being disposed on two orthogonalplanes in FIGS. 2A-D, may be disposed on a curved surface or more thantwo planes in other embodiments.

An external fiber optic plug 210 is illustrated in relation to theoptoelectronic device 100, which may be coupled with the optoelectronicdevice 100 via the optical adapter 110. As illustrated, the externalfiber optic plug 210 includes securing features 212 that secure theexternal fiber optic plug 210 to the optical adapter 110, and fiberwaveguides 215 that extend from a plug surface 217 to fiber cables 218.In the illustrated example, the securing features 212 are male prongsthat the cable connectors 112 are configured to receive to secure theplug surface 217 of the external fiber optic plug 210 against the freesurface 117 of the optical adapter 110. In other embodiments, in whichthe securing features 212 are female connectors, the cable connectors112 are male connectors configured for insertion into the securingfeatures 212 to secure the plug surface 217 against the free surface117. When secured against the free surface 117, a fiber waveguide 215 isoptically coupled with a waveguide 115 in the optical adapter 110. Invarious embodiments, some or all of the fiber waveguides 215 mayoptically couple with some or all of the waveguides 115. For example, anexternal fiber optic plug 200 may include N fiber waveguides 215 and theoptical adapter 110 may include N waveguides 115 to allow each fiberwaveguide 215 to optically couple with one waveguide 115. In anotherexample, an external fiber optic plug 200 may include N fiber waveguides215 and the optical adapter 110 may include N+M waveguides 115 (e.g., towork with multiple standards of external fiber optic plug 200), and M ofthe waveguides 115 may remain uncoupled when N of the waveguides 115 areoptically coupled with the N fiber waveguides 215.

FIG. 2B illustrates a cross-section of the example optoelectronic device100, showing details of the installed optical adapter 110 and PIC 120.Although FIG. 2B shows one planar view with various features, otherplanar views may show more or fewer features, such as the cableconnectors 112 (not shown in FIG. 2B) that extend through various otherplanes. The waveguide 115 is fabricated within the optical adapter 110and is optically exposed on a free surface 117 of the optical adapter110 and mated at the optical coupling interface 118 of the opticaladapter 110 with the integrated waveguide 125 of the PIC 120. As usedherein, optical exposure does not require physical exposure; a waveguide115, 125 may be encased in a substrate and receive and transmit lightthrough that substrate. Accordingly, a waveguide 115, 125 may beoptically exposed when a given end of the waveguide 115, 125 is within apredefined distance (e.g., about 5 micrometers) of a given surface ofthe optical adapter 110 or PIC 120 so as to be able to transmit orreceive light from one side of the given surface to the other side.Various lenses and filters (not illustrated) may be used in someembodiments at one or more of a first end or a second end of a waveguide115 to aid in gathering or transmitting light to a fiber waveguide 215or an integrated waveguide 125.

FIG. 2C illustrates a cross-section of a substrate, such as a glass oroptical resin, from which the optical adapter 110 may be fabricated thatdefines male connector engagement features 111. FIG. 2D illustrates analternative cross-section of a substrate from which the optical adapter110 may be fabricated that defines female connector engagement features111. In either embodiment, a laser is used to impart an etching patternin the material of the substrate to define a patterned region 113 and anun-patterned region 114. The patterned region 113 has a higherreactivity to a chemical etchant than the un-patterned region 114, andthe borders between the regions define various faces and features of theoptical adapter 110. The laser may also (simultaneously or at adifferent time) impart a waveguide pattern to define one or morewaveguides 115 in the material of the substrate. The waveguide patternimparts a different refractive index to portions of the material toguide light from one surface to another. In various embodiments, thewaveguides 115 may be optically exposed in the material of the substratevia physical etching, polishing, or chemical etching.

The laser forms the patterned region 113 by imparting energy to thematerial of the substrate, thereby affecting chemical bonds in thematerial and increasing the reactivity of the material in the patternedregion 113 (relative to the reactivity of the material in theun-patterned region 114) to an etchant. The etchant is then applied toan etching surface 119 of the substrate to remove the patterned region113 and leave behind the un-patterned region 114. Because the bordersbetween the patterned region 113 and the un-patterned region 114 definethe various contacting surfaces (e.g., a mating interface 116, anoptical coupling interface 118), engagement features 111, and cableconnectors 112 in the optical adapter 110, once the patterned region 113is removed, the optical adapter 110 includes the engagement features 111and the cable connectors 112. The patterned region 113 may define thevarious engagement features 111 and cable connectors 112 as maleconnectors (e.g., extending outward from a face of the optical adapter110) or as female connectors (e.g., extending inward from a face of theoptical adapter 110).

The engagement features 111 are defined on the mating interface 116 inrelation to the waveguides 115 of the optical adapter 110 so that whenthe optical adapter 110 is affixed to the PIC 120, the waveguides 115are aligned to optically couple with the integrated waveguides 125 ofthe PIC 120. Similarly, the cable connectors 112 are defined in the freesurface 117 of the optical adapter 110 in relation to where thewaveguides 115 are located on the free surface 117. In some embodiments,the relative locations of the cable connectors 112 and the waveguides115 are set according to various standards used for the cabling intendedfor connection to the optoelectronic device 100 (e.g., the fiber opticplug 210).

FIGS. 3A-D illustrate various views of an example optoelectronic device100 with an optical adapter 110 configured to optically couple with aPIC 120 for evanescent transmission. As will be appreciated, in a givenview, a given feature may be occluded or obscured by another feature,and a better understanding of how the features of an optoelectronicdevice interact may be gained by considering FIGS. 3A-D in aggregatethan individually.

FIG. 3A illustrates an isometric view of a translucent optical adapter110 that is affixed to and optically coupled with the PIC 120. As shown,engagement features 111 of the optical adapter 110 are engaged withmating features 121 of the PIC 120, and epoxy joints 130 are formedbetween the optical adapter 110 and the PIC 120. Epoxy joints 130 areformed via a deposited epoxy (e.g., in an epoxy well) being cured tobond one component to another. The optical adapter 110 shows cableconnectors 112 extending inward from a free surface 117, and a set ofwaveguides 115 that run from the free surface 117 of the optical adapter110 to an optical coupling interface 118 of the optical adapter 110 thatis held in contact with integrated waveguides 125 in the PIC 120 thatextend to the mating surface 126 of the PIC 120. A mating interface 116and an optical coupling interface 118 of the optical adapter 110 may becollectively referred to as a connecting surface. In some embodimentsthat use evanescent transmission, the mating interface 116 and theoptical coupling interface 118 of the optical adapter 110 may becoplanar, but in other embodiments may be located on separate parallelplanes.

An external fiber optic plug 210 is illustrated in relation to theoptoelectronic device 100, which may be coupled with the optoelectronicdevice 100 via the optical adapter 110. As illustrated, the externalfiber optic plug 210 includes securing features 212 that secure theexternal fiber optic plug 210 to the optical adapter 110, and fiberwaveguides 215 that extend from a plug surface 217 to fiber cables 218.In the illustrated example, the securing features 212 are male prongsthat the cable connectors 112 are configured to receive to secure theplug surface 217 of the external fiber optic plug 210 against the freesurface 117 of the optical adapter 110. In other embodiments, in whichthe securing features 212 are female connectors, the cable connectors112 are male connectors configured for insertion into the securingfeatures 212 to secure the plug surface 217 against the free surface117. When secured against the free surface 117, a fiber waveguide 215 isoptically coupled with a waveguide 115 in the optical adapter 110. Invarious embodiments, some or all of the fiber waveguides 215 mayoptically couple with some or all of the waveguides 115. For example, anexternal fiber optic plug 200 may include N fiber waveguides 215 and theoptical adapter 110 may include N waveguides 115 to allow each fiberwaveguide 215 to optically couple with one waveguide 115. In anotherexample, an external fiber optic plug 200 may include N fiber waveguides215 and the optical adapter 110 may include N+M waveguides 115 (e.g., towork with multiple standards of external fiber optic plug 200), and M ofthe waveguides 115 may remain uncoupled when N of the waveguides 115 areoptically coupled with the N fiber waveguides 215.

FIG. 3B illustrates a cross-section of the example optoelectronic device100, showing details of the installed optical adapter 110 and PIC 120.Although FIG. 3B shows one planar view with various features, otherplanar views may show more or fewer features, such as cable connectors112 (not shown in FIG. 3B) that extend through various other planes. Thewaveguide 115 is fabricated within the optical adapter 110 and isoptically exposed on a free surface 117 of the optical adapter 110 andmated at the optical coupling interface 118 of the optical adapter 110with the integrated waveguide 125 of the PIC 120.

FIG. 3C illustrates a cross-section of a substrate, such as a glass oroptical resin, from which the optical adapter 110 may be fabricated thatdefines male connector engagement features 111. A laser is used toimpart an etching pattern in the material of the substrate to define apatterned region 113 and an un-patterned region 114. The patternedregion 113 has a higher reactivity to a chemical etchant than theun-patterned region 114, and the borders between the regions definevarious faces and features of the optical adapter 110. The etchingpattern is applied to an etching surface 119 of the substrate, to whichthe chemical etchant is applied to remove the patterned region 113during a chemical etch process. The laser may also (simultaneously or ata different time) impart a waveguide pattern to define one or morewaveguides 115 in the material of the substrate in the un-patternedregion 114. The waveguide pattern imparts a different refractive indexto portions of the material to guide light from one surface to another.In various embodiments, the waveguides 115 may be optically exposed inthe material of the substrate via physical etching, polishing, orchemical etching.

FIG. 3D illustrates an underside of an optical adapter 110 configuredfor evanescent transmission that shows various features present on themating interface 116 of the optical adapter 110. Four engagementfeatures 111 with various shapes and orientations on the matinginterface 116 are present, and are oriented for engagement with matingfeatures 121 on the PIC 120. Although the example engagement features111 are shown as having quadrilateral and circular cross sections, othershapes and sizes of engagement features 111 are possible. Similarly,more or fewer than four engagement features 111 may be present on themating interface 116, and the engagements features 111 may be maleconnectors, female connectors, or a combination of male and femaleconnectors. The shapes, sizes, and positions of the engagements features111 on the mating interface 116 relative to one another may be such thatthe optical adapter 110 has only one orientation that matches with themating features 121 of the PIC 120.

The engagement features 111 are defined on the mating interface 116 inrelation to the waveguides 115 of the optical adapter 110 so that whenthe optical adapter 110 is affixed to the PIC 120, the waveguides 115are aligned to optically couple with the integrated waveguides 125 ofthe PIC 120. Similarly, the cable connectors 112 are defined in the freesurface 117 of the optical adapter 110 in relation to where thewaveguides 115 are located on the free surface 117. In some embodiments,the relative locations of the cable connectors 112 and the waveguides115 are set according to various standards used for cabling intended forconnection to the optoelectronic device 100 (e.g., a fiber optic plug210).

FIGS. 4A-D illustrate various views of the photonic elements of anoptical adapter 110 constructed as a multi-piece unit. As will beappreciated, in a given view, a given feature may be occluded orobscured by another feature, and a better understanding of how thefeatures of an optoelectronic device interact may be gained byconsidering FIGS. 4A-D in aggregate than individually.

FIG. 4A is an isometric view of a first photonic element 410 and asecond photonic element 420 that are configured to connect together toform an optical adapter 110. The illustrated first photonic element 410includes the engagement features 111, a first portion of the cableconnectors 112, and the waveguides 115. The illustrated second photonicelement 420 includes a second portion of the cable connectors 112, sothat when the first photonic element 410 is connected with the secondphotonic element 420, the first and second portions define the cableconnectors 112.

FIG. 4B is an isometric view of a first photonic element 410 and asecond photonic element 420 in which the first photonic element 410 andthe second photonic element 420 are connected to form an optical adapter110. Also illustrated in FIG. 4B are several through-holes 430 in theoptical adapter 110 running through the cable connectors 112 in thefirst photonic element 410 and the second photonic element 420. Invarious embodiments, the through-holes 430 are defined via physicaletching or chemical etching of the patterned region 113 to provide afluid outlet (e.g., the etchant during etching or air when a maleconnector is inserted into the cable connectors 112). Althoughillustrated as vertical elements, in other embodiments, thethrough-holes 430 may be provided in other orientations.

FIG. 4C is a first cross-sectional view of a substrate in which a firstphotonic element 410 and a second photonic element 420 are defined. Thepresent example shows the first photonic element 410 and the secondphotonic element 420 defined in a combined die on one substrate forpurposes of explanation. In other embodiments, dies for a first photonicelement 410 are defined in a separate substrate from the dies for asecond photonic element 420. FIG. 4D is a second cross-sectional view ofthe substrate illustrated in FIG. 4C showing different details of thefirst photonic element 410 and the second photonic element 420 definedtherein.

FIG. 4C illustrates several through-holes 430, including through-holes430 positioned in the regions corresponding to the portions of patternedregion 113 that will be removed to form the cable connectors 112 and athrough-hole 430 in a central region of the substrate (between theportions of the un-patterned regions 114 that will form the firstphotonic element 410 and the second photonic element 420) to channel theetchant from a first surface 440 of the substrate to a second surface450 of the substrate. For example, a central through-hole 430 may bephysical etched to prior to chemical etching to channel the etchant fromthe first surface 440 on the top side of the substrate to a secondsurface 450 opposite the first surface 440 to define an engagementfeature 111 thereon. FIG. 4C also illustrates a first pair on internalalignment features 460 of matched male and female interconnects that mayposition and align the first photonic element 420 with the secondphotonic element 420 when assembled.

FIG. 4D illustrates a second plane of the substrate in whichthrough-holes 430 are absent, but partial channels 470 are present. Thepartial channels 470 define regions in the substrate that may bephysically etched (e.g., to direct the flow of a chemical etchant), butdo not run completely from the first surface 440 to the second surface450 of the substrate. In some embodiments, the partial channels 470interface with the through-holes 430 to direct an etchant to particularportions of the substrate. For example, the partial channel 470illustrated in FIG. 4D may flow into the central through-hole 430illustrated in FIG. 4C to direct an etchant to the patterned region 113on the second surface 450 of the substrate. In some embodiments, achannel 480 of an un-patterned region 114 may physically link one ormore dies on the substrate for the duration of the etching process, andmay be removed by a physical processing or dicing process once chemicaletching has concluded.

FIG. 4D also illustrates a waveguide 115, and a second pair of internalalignment features 460 of matched male and female interconnects that mayposition and align the first photonic element 420 with the secondphotonic element 420 when assembled. Although the illustrated waveguide115 is configured for direct transmission, waveguides 115 configured forevanescent transmission may also be defined in multi-piece constructionsfor an optical adapter 110.

FIGS. 5A-E illustrate various views of an example optoelectronic device100 with an optical adapter 110 configured with open cable connectors112. As will be appreciated, in a given view, a given feature may beoccluded or obscured by another feature, and a better understanding ofhow the features of an optoelectronic device interact may be gained byconsidering FIGS. 5A-E in aggregate than individually.

FIG. 5A illustrates an isometric view of a translucent optical adapter110 that is affixed to and optically coupled with the PIC 120. As shown,engagement features 111 of the optical adapter 110 are engaged withmating features 121 of the PIC 120, and epoxy joints 130 are formedbetween the optical adapter 110 and the PIC 120. Epoxy joints 130 areformed via a deposited epoxy (e.g., in an epoxy well) being cured tobond one component to another. The optical adapter 110 shows cableconnectors 112 extending from a free surface 117, and a set ofwaveguides 115 that run from the free surface 117 of the optical adapter110 to an optical coupling interface 118 of the optical adapter 110 thatis held in contact with integrated waveguides 125 in the PIC 120. Amating interface 116 and an optical coupling interface 118 of theoptical adapter 110 may be collectively referred to as a connectingsurface, and although illustrated as being disposed on two orthogonalplanes in FIGS. 5A-E, may be disposed on a curved surface or more thantwo planes in other embodiments.

An external fiber optic plug 210 is illustrated in relation to theoptoelectronic device 100, which may be coupled with the optoelectronicdevice 100 via the optical adapter 110. As illustrated, the externalfiber optic plug 210 includes securing features 212 that secure theexternal fiber optic plug 210 to the optical adapter 110, and fiberwaveguides 215 that extend from a plug surface 217 to fiber cables 218.In the illustrated example, the securing features 212 are male prongsthat the cable connectors 112 are configured to receive to secure theplug surface 217 of the external fiber optic plug 210 against the freesurface 117 of the optical adapter 110. In other embodiments, in whichthe securing features 212 are female connectors, the cable connectors112 are male connectors configured for insertion into the securingfeatures 212 to secure the plug surface 217 against the free surface117. When secured against the free surface 117, a fiber waveguide 215 isoptically coupled with a waveguide 115 in the optical adapter 110. Invarious embodiments, some or all of the fiber waveguides 215 mayoptically couple with some or all of the waveguides 115. For example, anexternal fiber optic plug 200 may include N fiber waveguides 215 and theoptical adapter 110 may include N waveguides 115 to allow each fiberwaveguide 215 to optically couple with one waveguide 115. In anotherexample, an external fiber optic plug 200 may include N fiber waveguides215 and the optical adapter 110 may include N+M waveguides 115 (e.g., towork with multiple standards of external fiber optic plug 200), and M ofthe waveguides 115 may remain uncoupled when N of the waveguides 115 areoptically coupled with the N fiber waveguides 215.

In contrast to the closed cable connectors 112 illustrated in FIGS. 2Aand 3A, the cable connectors 112 illustrated in FIG. 5A are open. Opencable connectors 112 are exposed on the free surface 117 (to allowinsertion of the securing features 212), and are also exposed on asurface orthogonal to the free surface 117. During the manufacturingprocess, a patterned region 113 is defined in the substrate of theoptical adapter 110 such that the patterned region 113 runs from theetching surface 119 to the free surface 117 and a surface orthogonal tothe free surface 117. The portion of the patterned region 113 that runsto the orthogonal surface defines a channel opening by which a chemicaletchant applied to the substrate may carry away material removed fromthe substrate, and allowing the chemical etchant to etch from theetching surface 119 to the free surface 117. Although the orthogonalsurface in which the channel opening is defined is shown on the “side”of the example optical adapter 110 in FIGS. 5A-E, in other embodimentsthe “top” or the “bottom” side may include the channel opening.Similarly, the size of the channel opening may vary in differentembodiments from the examples illustrated in FIGS. 5A-E.

FIG. 5B illustrates a cross-sectional side view of an optical adapter110 with open cable connectors 112, and FIG. 5C illustrates an isometricview of an optical adapter with open cable connectors 112 as may bepositioned during chemical etching. The open cable connectors 112 aredefined by a pattern imparted by a laser in the substrate from which theoptical adapter 110 is formed. The pattern alters the chemical bonds ofthe substrate material to increase the material's reactivity to achemical etchant. In the illustrated embodiment, the pattern extendsfrom an etching surface 119 to the free surface 117, and defines achannel opening in a plan orthogonal to the free surface 117, whichallow a chemical etchant applied to the etching surface 119 to run offand away from the optical adapter 110 once the chemical etchant hasreacted with the substrate in the patterned region; allowing freshetchant to come into contact with the remaining patterned region andallowing spent etchant to carry material away from the optical adapter110. The free surface 117 may be mounted below the etching surface 119during a chemical etch process to allow gravity to assist the flow ofetchant through the patterned region. The patterned region that definesthe open cable connectors 112 may be in fluid communication and part ofthe patterned region that defines the mounting surfaces or may beseparate from the other patterned regions defined in the substrate ofthe optical adapter 110. For example, un-patterned regions may separatethe patterned regions that define the waveguides 115 from the patternedregions that define the open cable connectors 112.

FIG. 5D is an isometric view of a first photonic element 410 and asecond photonic element 420 that are configured to connect together toform an optical adapter 110. The illustrated first photonic element 410includes a first portion of the cable connectors 112 and the waveguides115. The illustrated second photonic element 420 includes a secondportion of the cable connectors 112, so that when the first photonicelement 410 is connected with the second photonic element 420, the firstand second portions define the open cable connectors 112. The relativeamounts of patterning applied to the first photonic element 410 and thesecond photonic element 420 may be varied to account for a greater orlesser portion of the cable connectors 112 to be defined by one of thefirst photonic element 410 or the second photonic element 420. In someembodiments, the open cable connector 112 is defined solely by etchingon one of first photonic element 410 or second photonic element 420,with the other of flat first photonic element 410 or second photonicelement 420 providing a flat un-etched surface to define a surface ofthe open cable connector 112.

In some embodiments, the second photonic element 420 may be constructedto be longer than the first photonic element 410 (along the Y axis) todefine the mating interface 116 (and may include engagement features 111and epoxy joints 130 defined thereon). Additionally, various alignmentfeatures and male/feature interconnects may be defined on the matingsurfaces of the first photonic element 410 and the second photonicelement 420 to ensure that the free surfaces 117 of the respectivephotonic elements are aligned into a single surface when the firstphotonic element 410 and the second photonic element 420 are joinedtogether.

In various embodiments, dies for a first photonic element 410 may bedefined on the same or a separate substrate from the dies for a secondphotonic element 420. In some embodiments, the etching surfaces 119 foreach of the first photonic element 410 and the second photonic element420 may be the surfaces by which the two elements are mated together. Inother embodiments, the free surface 117 (or the opposite surface) foreach of the first photonic element 410 may be the etching surface forthe respective photonic element.

FIG. 5E is an isometric view of an optical adapter 110 that isconfigured to mount with the PIC 12 to form cable connectors 112. Theillustrated optical adapter 110 includes a first portion of the cableconnectors 112 and the waveguides 115, and uses the mating surface 126of the PIC 120 to form additional surfaces/portions of the cableconnectors 112. The mating interface 116 of the optical adapter 110 mayinclude various engagement features 111 (not illustrated) to interfacewith the mating features 121 (not illustrated) of the PIC 120 to alignthe waveguides 115 with the integrated waveguides 125 for evanescentcoupling. In various embodiments, the optical adapter 110 of FIG. 5E maybe constructed such that the etching surface 119 and the matinginterface 116 are the same surface or parallel surfaces (e.g., theetching surface 119 may be removed to reveal the mating interface 116).

FIGS. 6A-G illustrate various coupling arrangements of waveguides 115within an optical adapter 110. The individual paths of waveguides 115within an optical adapter 110 may vary in different embodiments in thenumber of waveguides 115, the arrangement of waveguides 115, thethree-dimensional path that each waveguide 115 runs in the opticaladapter 110, etc., and the example coupling arrangements shown in FIGS.6A-G are illustrative of but a few arrangements. It will be appreciatedthat the coupling arrangements may be applied in embodiments that useevanescent or direct transmission of light. A given embodiment of anoptical adapter 110 may use one or more of the example couplingarrangements in combination with one another.

FIG. 6A illustrates several waveguides 115 arranged for straightcoupling, in which the number, spacing, and order of the waveguides 115remain consistent from the free surface 117 to the optical couplinginterface 118. FIG. 6B illustrates several waveguides 115 arranged forcondensed coupling, in which the number and order of the waveguides 115remain consistent, but the spacing decreases from the free surface 117to the optical coupling interface 118. FIG. 6C illustrates severalwaveguides 115 arranged for expanded coupling, in which the number andorder of the waveguides 115 remain consistent, but the spacing increasesfrom the free surface 117 to the optical coupling interface 118. FIG. 6Dillustrates several waveguides 115 arranged with swapped ordering, inwhich the number of waveguides 115 remain consistent, the relative orderof the waveguides 115 at the free surface 117 is different than at theoptical coupling interface 118. The spacing and order of the variouswaveguides 115 may be adjusted to account for various standards used onthe connector side and the PIC side of an assembly, to allow a PIC 120to use a different standard than the external fiber optic plug 210.

FIG. 6E illustrates several waveguides 115 arranged for combinedcoupling, in which several waveguides 115 defined at the free surface117 combine into one waveguide 115 at the optical coupling interface.FIG. 6F illustrates several waveguides 115 arranged for split coupling,in which one waveguides 115 defined at the free surface 117 splits intomultiple waveguides 115 at the optical coupling interface. Waveguides115 may split/combine signals for various purposes in signal processing,such as for amplifying, extinguishing, or accepting multiple signals fora single output.

FIG. 6G illustrates several waveguides 115 arranged with several unusedpathways. In some embodiments, the unused pathways have no waveguide 115defined between the free surface 117 and the optical coupling interface118. In other embodiments, waveguides 115 are defined between the freesurface 117 and the optical coupling interface 118, but a correspondingintegrated waveguide 125 or fiber waveguide 215 is not present or couplewith the waveguide 115 on the unused path.

FIG. 7 illustrates an example substrate layout 700. The example layout700 shows four dies 710 for various photonic elements, although more orfewer dies 710 may be present on other substrates with different layouts700. Each of the dies 710 is shown with a first surface on which severalfeatures have been produced via etching. These features may includefeatures that protrude from the first surface of the die 710 as well asfeatures that extend into the die 710 from the first surface based onthe patterned region 113 applied to the material of the substrate.Several dice-lines 720 are illustrated between the dies 710 thatindicate where a physical etching operation may be performed to separatethe dies 710 from the substrate and one another.

FIGS. 8A-D illustrate detailed views of engaging engagement features 111and mating features 121 of the PIC 120. Each of the detailed views isillustrated relative to a thickness (T) of the features and a width (W)of the features, which may correspond to various planes in theoptoelectronic device 100 depending on the orientation of the engagementfeature 111 and the mating feature 121.

FIG. 8A illustrates engaging an engagement feature 111 with a matingfeature 121, according to one embodiment disclosed herein. Specifically,FIG. 8A illustrates a cross section of a male engagement feature 111 anda female mating feature 121, but other embodiments may switch which ofthe engagement feature 111 and the mating feature 121 is male/female. Inone embodiment, these features may form a frustum and a rectangulartrench, respectively.

FIG. 8A illustrates a desired target location 810 where a middle of theengagement feature 111 aligns with a middle of the mating feature 121.That is, for optimal alignment, the middle of the engagement feature 111contacts the middle of a bottom surface 830 of the mating feature 121.In this example, the mating feature 121 includes a trench or cutout inan Inter-Layer Dielectric (ILD) on the top of the PIC 120. The ILD maybe formed on a substrate of the PIC 120, which may be a semiconductorsubstrate such as crystalline silicon.

In this example, a bottom surface 850 of the engagement feature 111contacts the bottom surface 830 of the mating feature 121. Moreover, asdiscussed in more detail below, the engagement feature 111 includesself-correcting alignment features 820 (e.g., the slanted sides of theengagement feature 111) which contact sides 825 of the mating feature121 for correcting the alignment of the optical adapter 110 and the PIC120 when the middles of the engagement feature 111 and the matingfeature 121 are not aligned.

FIGS. 8B-D illustrate mating a misaligned engagement feature 111 with amating feature 121, according to embodiments disclosed herein. FIG. 8Billustrates a scenario where the middle of the engagement feature 111 isoffset 840 from the desired target location 810. The difference betweenthe offset 840 and the target location 810 is illustrated as amisalignment 845. Stated differently, the misalignment 845 is thedistance between respective middles of the engagement feature 111 andthe mating feature 121.

The misalignment 845 can occur because of tolerances corresponding tothe bonding machine or apparatus (e.g., a die bonder) used to place theoptical adapter 110 on the PIC 120. For example, the die bonder mayguarantee that the middle of the engagement feature 111 is within ±10micrometers from the middle of the mating feature 121 (e.g., the desiredtarget location 810). FIG. 8B illustrates a worst case scenario wherethe misalignment 845 is the maximum tolerance of the bonding machine.

To compensate for the tolerance or accuracy of the bonding machine, theengagement feature 111 is designed such that regardless of themisalignment 845, the self-correcting alignment feature 820 contacts aside 825 of the mating feature 121. That is, the width (W) of theengagement feature 111 can be controlled such that the flat, bottomsurface 850 of the engagement feature 111 falls within the matingfeature 121, and as a result, at least one of the self-correctingalignment features 820 contacts one of the sides 825.

The accuracy of the alignment in FIG. 8B, where the bottom surface 850of the engagement feature 111 contacts the bottom surface 830 of themating feature 121, may depend on the amount of control of the flatnessof the bottom surface 850 on the engagement feature 111 and thetolerance on the etch depth of the mating feature 121 (which can bearound +/−0.5 micrometers for many dielectrics). Moreover, the slope ofthe self-correcting alignment features 820 can be tightly controlledusing an orientation dependent etch, such as a KOH etch, a denserapplication of the patterned region 113, and the like.

In FIG. 8B, when the die bonder moves the optical adapter 110 in thevertical direction illustrated by the arrow 860, the bottom surface 850is between the sides 825A and 825B. Thus, even at maximum misalignment845, the bottom surface 830 is within the mating feature 121.

As the optical adapter 110 continues to move in the direction shown bythe arrow 860, the self-correcting alignment feature 820A contacts theside 825A which is illustrated in FIG. 8C. The die bonder continues toapply downward pressure, but the resulting contact between the alignmentfeature 820A and the side 825A creates a horizontal motion as shown bythe arrow 865, which moves the middle of the engagement feature 111closer to the middle of the mating feature 121. That is, in oneembodiment, the die bonder does not apply the horizontal motion directly(e.g., the die bonder may apply pressure in the vertical direction) forthe optical adapter 110 to move horizontally relative to the PIC 120 tocorrect for the misalignment 845. The vertical pressure applied by thedie bonder is converted into the horizontal motion illustrated by thearrow 865 to align the piece parts.

FIG. 8C illustrates when the die bonder has moved the parts until thebottom surface 850 of the engagement feature 111 contacts the bottomsurface 830 of the mating feature 121. The middles of the engagementfeature 111 and the mating feature 121 may both be aligned at the targetlocation 810, although there may be some remaining misalignment due tothe tolerances of the fabrication steps used to form the engagementfeature 111 and the mating feature 121. However, the tolerances forprocessing the engagement feature 111 and the mating feature 121 may bemuch smaller or tighter than the tolerances for the die bonder—e.g.,within +/−500 nanometers. For example, the engagement feature 111 may bedefined via a laser imparting a patterned region 113 in the material ofthe optical adapter 110. Similarly, the techniques for defining andetching the mating feature 121 can have much tighter tolerances than thedie bonder.

Each of the engagement feature 111 and the mating feature 121 arealigned relative to the waveguides 115, 125 to ensure optical couplingtherebetween without the use of active testing. For example, theengagement feature 111 is defined relative to the waveguide 115 and themating feature 121 is defined relative to the integrated waveguide 125with a high enough degree of precision (e.g., with a tolerance within+/−500 nanometers) to ensure that when the optical adapter 110 isaffixed to the PIC 120, that the waveguide 115 is optically aligned withthe integrated waveguide 125. The laser may define the engagementfeature 111 and the waveguide 115 simultaneously (or at separate times,using a shared alignment point) to ensure the high degree of precision.Similarly, a laser may define the mating feature 121 and the integratedwaveguide 125 simultaneously (or at separate times, using a sharedalignment point). The alignment features 820 ensure that the precisionin fabrication of the engagement feature 111 is maintained duringassembly of the optical adapter 110 with the PIC 120.

FIG. 9A illustrates mating the engagement feature 111 with the matingfeature 121. Unlike in FIG. 8D, where the bottom surface 850 of theengagement feature 111 contacts the bottom surface 830 of the matingfeature 121, in this example, there remains a gap between the bottomsurface 850 of the engagement feature 111 and the bottom surface 830 ofthe mating feature 121. Instead, the thickness of the engagement feature111 is controlled such that a mating interface 116 of the opticaladapter 110 at a base of the frustum formed by the engagement feature111 contacts a mating surface 126 of the PIC 120.

In one embodiment, given the tolerances associated with the fabricationsteps forming the engagement feature 111 and the mating feature 121, atleast one of the self-correcting alignment features 820 may contact oneof the sides 825 when aligned, while at least one other of theself-correcting alignment features 820 does not. However, in otherembodiments, multiple alignment features 820 may contact respectivesides 825 when aligned.

FIG. 9B illustrates engaging the engagement feature 111 with the matingfeature 121. In this example, the width of the engagement feature 111 isagain controlled such that the bottom surface 850 fits inside the sides825 regardless of any misalignment. However, instead of alignment beingachieved when a mating interface 116 of the optical adapter 110 contactsa mating surface 126 of the PIC 120, here the optical adapter 110 isaligned when the self-correcting alignment feature 820 on one side ofthe engagement feature 111 and the self-correcting alignment feature 820on the opposite side of the engagement feature 111 both contactrespective sides 825 of the mating feature 121. Although FIG. 9Billustrates the self-correcting alignment feature 820A contacting theside 825A and the self-correcting alignment feature 820B contacting theside 825B, more or fewer self-correcting alignment features 820 (e.g., acircular mating feature 121 may have one continuous edge formingmultiple “sides” 825 when viewed in cross-section) in the engagementfeature 111 may contact respective sides 825 of the mating feature 121.Contacting two oppositely disposed self-correcting alignment features820 to two sides 825 of the receiver provide alignment in a given plane.Moreover, when a third self-correcting alignment feature 820 (which isdisposed between the two oppositely disposed alignment features)contacts a side 825 of the mating feature 121, this can providealignment in a further direction or plane.

FIG. 9C illustrates engaging the engagement feature 111 with the matingfeature 121. FIG. 9C relies on a similar alignment principle in FIG. 9Bwhere at least two opposing self-correcting alignment features 820contact respective sides 925 of a trench—e.g., a deep alignment receiver905. However, instead of forming the engagement feature 111 solelywithin an ILD, in FIG. 9C, the deep alignment receiver 905 extends intothe substrate of the PIC 120. In one embodiment, the deep alignmentreceiver 905 may have a depth greater than 15 micrometers. Further, thedepth of the deep alignment receiver 905 may permit the engagementfeature 111 to have a pyramidal shape rather than a frustum shape asshown in FIG. 9C. That is, the self-correcting alignment features 820may intersect at a point rather than forming a flat bottom surface 850facing the bottom surface 830 of the deep alignment receiver 905.

One advantage of using the alignment technique illustrated in FIGS. 9Band 9C is that the spacing between the mating interface 116 of theoptical adapter 110 and the mating surface 126 of the PIC 120 can befilled with epoxy for bonding the two components together (e.g.,providing an epoxy well produced by physically processing or chemicallyetching the substrates). However, relying on contact between theself-correcting alignment features 820 and the sides can cause stresswhich may increase the likelihood of chipping the sides 825.

FIG. 10 is a flowchart illustrating high level operations of an examplemethod 1000 for the use of laser patterning in optical components.Method 1000 begins at block 1010, where a laser is aligned with asubstrate. In various embodiments, a given feature (such as an etched orplated “+” mark, circle or fiducial) in a die 710 of the substrate orthe substrate itself is selected as an alignment point. The laser may bealigned in one plane (e.g., a two-dimensional alignment) or in threedimensions relative to the substrate.

At block 1020, the laser applies a pattern to the material of thesubstrate. The laser applies the pattern relative to the alignment pointto define an etching pattern to the substrate. The etching patterndesignates portions of the substrate as patterned regions 113, and theportions to which the etching pattern is not applied as un-patternedregions 114. By applying the etching pattern, the laser alters achemical bond in the material of the substrate for the patterned region113 that increases a reactivity of the material in the patterned region113 to an etchant relative to a reactivity of the material in theun-patterned regions 114. The patterned region 113 thus may define theengagement feature 111, cable connectors 112, etc., in the un-patternedregion 114 that will remain after chemical etching, which are configuredto engage with a mating feature 121 on an optoelectronic device 100 oran external cable.

In addition to applying the etching pattern at block 1020, the laser mayalso apply waveguide patterns to the substrate at block 1020. Thewaveguide pattern defines one or more pathways (i.e., waveguides 115)through the material of the die 710 with different refractive indicesthat the surrounding material to direct the propagation of light throughthe material. The waveguides 115 may have first ends that are co-alignedwith the engagement features 111, to ensure optical coupling with theintegrated waveguides 125 of the PIC 120 when mounted. Similarly, thewaveguides 115 may have second ends that that are co-aligned with thecable connectors 112, to ensure optical coupling with an external cable.

In some embodiments, the laser defines where the waveguide pattern islocated simultaneously with where the etching pattern is appliedrelative to the alignment point and imparts the patterns simultaneously.In other embodiments, the etching pattern is applied relative to thealignment point, and the waveguide pattern is later applied relative tothe etching pattern (e.g., after a chemical etch). In furtherembodiments, the waveguide pattern is applied relative to the alignmentpoint, and the etching pattern is later applied relative to thewaveguide pattern.

At block 1030, optional physical processing may occur. A drill, laserablator, saw, water jet, or the like may physically etch or processesthrough-holes 430 or channels 480 in a first surface of the die 710 todirect the flow of a chemical etchant, to remove excess material beforea chemical etchant is applied, or to apply features to the die 710 thatrequire less precision than the engagement features 111, cableconnectors 112, and waveguides 115. In some embodiments, block 1030 maybe performed after block 1040 to separate various dies 710 from oneanother in a substrate layout 700, to impart labels, or the like.

At block 1040, a chemical etchant is applied to the die 710. The etchantreacts with the material of the die 710, thereby removing material fromthe physically exposed surfaces of the die 710 and physically exposingthe underlying material. The patterned regions 113 (i.e., those portionsof the die 710 to which the laser applied the etching pattern) reactmore vigorously with the etchant, in some cases up to 5000 times morevigorously, and thus lose material faster than the un-patterned regions114. The patterned regions 113 thus define what material is left behindin the un-patterned regions 114 once chemical etching concludes,including the engagement features 111, cable connectors 112, and varioussurfaces of the photonic element defined in the die 710.

At block 1050, after chemical etching (per block 1040), the photonicelement (waveguides, lenses, and other optical features) is detailed. Invarious embodiments, detailing the photonic element may include dicingthe photonic element from the substrate, polishing at least one surfaceof the photonic element, or affixing the photonic element to a secondphotonic element (e.g., in a multi-piece design).

At block 1060, the photonic element is integrated into theoptoelectronic device 100. A die bonder may align the engagementfeatures 111 with the mating features 121 of the PIC 120 and connect theengagement features 111 with the mating features 121. In variousembodiments, the engagement features 111 (or the mating features 121)are designed with various self-correcting alignment features 820 thatimprove the precision at which the die bonder may integrate theengagement features 111 with the mating features 121. The precision atwhich the engagement features 111 with the mating features 121 areconnected influences where the waveguides 115 and the integratedwaveguides 125 are positioned relative to one another. By fabricatingthe engagement features 111 of an optical adapter 110 with the precisionafforded by laser patterning, (e.g., with tolerances with ±500nanometers) a die bonder may affix the optical adapter 110 with similarprecision, and thus passively align the waveguides 115 of the opticaladapter 110 with the integrated waveguides 125 of the PIC 120 (i.e.,without requiring active alignment and test). As part of affixing thephotonic element to optoelectronic device 100, the die bonder may applyand cure an epoxy to form epoxy joints 130 that secure the separatecomponents together. In other embodiments, the thermocompression orwafer bonding processes may be used in addition to or instead of die orepoxy bonding.

After the photonic element is integrated into the optoelectronic device100, various tests of the optical coupling, dimensioning, loss ratios,extinction ratios, and the like may be performed, and method 1000 maythen conclude.

In the preceding, reference is made to embodiments presented in thisdisclosure. However, the scope of the present disclosure is not limitedto specific described embodiments. Instead, any combination of thedescribed features and elements, whether related to differentembodiments or not, is contemplated to implement and practicecontemplated embodiments. Furthermore, although embodiments disclosedherein may achieve advantages over other possible solutions or over theprior art, whether or not a particular advantage is achieved by a givenembodiment is not limiting of the scope of the present disclosure. Thus,the preceding aspects, features, embodiments and advantages are merelyillustrative and are not considered elements or limitations of theappended claims except where explicitly recited in a claim(s).

In view of the foregoing, the scope of the present disclosure isdetermined by the claims that follow.

We claim:
 1. A substrate, comprising: a light-transmissive materialhaving a first side and a second side opposite to the first side; aplurality of dies defined in the light-transmissive material, each dieof the plurality of dies including: a first pattern imparted on thelight-transmissive material by a laser, wherein the first patternextends into the light-transmissive material from the first side, thefirst pattern defining a patterned region of the light-transmissivematerial and an un-patterned region of the light-transmissive material,wherein a chemical structure of the patterned region has an increasedreactivity to an etchant relative to the un-patterned region, andwherein the patterned region defines an engagement feature in theun-patterned region that is configured to engage with a mating featureon a Photonic Integrated Circuit (PIC); and a second pattern imparted onthe light-transmissive material by the laser, wherein the second patternextends to neither the first side nor the second side, the secondpattern defining a waveguide within the light-transmissive materialresulting from a laser induced change in the chemical structure of thesecond pattern, wherein the waveguide is aligned relative to theengagement feature to optically couple with an integrated waveguide ofthe PIC.
 2. The substrate of claim 1, wherein the engagement feature isdefined as a first gender connector and the mating feature is defined asa second gender connector, wherein the first gender is one of male andfemale and the second gender is different from the first gender.
 3. Thesubstrate of claim 1, further comprising: a third pattern imparted onthe light-transmissive material by the laser, wherein the third patternextends into the light-transmissive material from the first side, thethird pattern defining a second patterned region of thelight-transmissive material and a second un-patterned region of thelight-transmissive material, wherein a chemical structure of the secondpatterned region has an increased reactivity to the etchant relative tothe second un-patterned region, and wherein the second patterned regiondefines a cable connector with the patterned region.
 4. The substrate ofclaim 1, further comprising: a physical processing region defining acable connector to be exposed from the substrate via mechanicalprocessing that removes the physical processing region.
 5. The substrateof claim 1, further comprising a second plurality of dies, wherein eachdie of the plurality of dies defines a first photonic element and eachdie of the second plurality of dies further defines a second photonicelement configured to mate with the first photonic element to define amulti-piece optical adapter, wherein the second photonic element isassembled with the first photonic element into the multi-piece opticaladapter to define additional connectors for the multi-piece opticaladapter not defined solely by the first photonic element.
 6. Thesubstrate of claim 1, wherein the waveguide runs from the second side toa third side orthogonal to the second side to enable evanescent couplingwith the integrated waveguide of the PIC.
 7. The substrate of claim 1,wherein the first pattern defines a mating interface in a plane parallelto the second side and the waveguide runs from the second side to themating interface.